But we don’t have an effective way to keep the devices powered for long periods of time — many can only remain airborne for 30 minutes or so. That may soon change, however. The U.S. Army thinks it has found a way to keep drones in the air indefinitely. And like all good plans, it involves lasers.

A LONG-DISTANCE POWER-UP. According to New Scientist, the U.S. Army is developing a system in which a laser shot from the ground can power up a military drone mid-flight. The key is hitting a photovoltaic cell on the drone, which then converts the light from the laser into electricity. The Army hopes to be able to do this from up to 500 meters (.31 miles) away.

THAT’S NOT GOOD. The Army still has several hurdles to overcome before its drone-powering laser system is ready for the battlefield, though. The biggest one: not melting the drone. See, any laser energy that isn’t converted to electricity by the drone’s photovoltaic cell becomes heat — heat that could do serious damage to a drone.

The Army’s research team is working on a way to ensure excess heat can dissipate without causing any damage to the military drone. Making sure the beam only hits where it’s supposed to will be critical for making that happen.

If the Army can perfect the system, it’ll have a way to keep drones flying indefinitely, which would be useful for applications like keeping an eye on enemies to standing watch over the Army’s own bases (not to mention lots of things that could eventually help civilians directly).

BABY STEPS. Right now, the Army is working to develop its system enough so that it can power a drone on the ground by early 2019. After that, the next step will be to power a drone in the air, which the Army thinks it’ll be able to do in 2020. Once it has an operational system in place, the Army will just need to get regulators’ blessing, and its laser-powered drones will be ready for take-off.